Wilhelm schmidt



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WQSCHMIDT. DOUBLE ACTING STEAM ENGINE. No. 535,864. y Patented Mar. 19, 1895.

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imei) STATES PATENT OFFICE WILHELM SCHMIDT, OF WILI-IELMSHHE, GERMANY.

DOUBLE-ACTING STEAM-ENGINE.

SEECIFICATION forming part of Letters Patent No. 535,864, dated-March 19, 1895.

Application filed .T une 8, 1894.

T0 all whom t may concern:

Be it known that I, WILHELM SCHMIDT, a subject of the King of Prussia, German Emperor, and a resident of Wilhelmshhe, near Cassel, in the Province of Hesse-Nassau, German Empire, have invented certain new and' useful Improvements in Double-Acting Steam-Engines, of which the following is an exact specification.

This invention relates to a double-acting steam-engine, the manner of working of which is similar to that of a compound-engine with receiver'.l There are, however, the dierences, that one si-de of the low-pressure is constantly under the influence of the low-pressure steam piston, and that the space between that side of the low-pressure piston and the opposite cylinder-cover forms part of the receiver, the capacity of the latter being, therefore, a variable one.

The objects of my invention are, first, to provide an engine, which is specially adapted for the use of su perheated steam, and, second, to cause in such engine the high-pressure cylinder to be cooled by the low-pressure steam, and the low-pressure cylinder to be heated by the receiver-steam, as will all be more fully described hereinafter.

In order to make my invention more clear, I refer to the accompanying drawing, in which is shown a longitudinal section through an engine constructed according to my invention.

In the ligure, a is the high-pressure cylinder, within which works the hollow high-pressure piston a5 of plunger-like configuration. rlhis piston extends into the low-pressure-cylin der, and carries at its end the low-pressure piston b3, by which latter the said cylinder is divided into two compartments or chambers b b2. Chamber b2 extends, as a matter of course, up into the hollow plunger, and constitutes the variablereceiver-part` mentioned in the preamble. This part is in constant communication with the receiver prop'er c by a port d, while the high-pressure cylinder a and the annular chamber b of the low-pressure cylinder are alternately brought into communication with the receiver proper c by the hollow slides e and f. These slides are made integrally, and are operated simultaneously by one and the same valve-rod g.

Su pposin g the valves be in their highest po- Serial No. 513,942. (No model.)

sition, the high-pressure steam entering the engine at h will flow into cylinder a through the groove around the contracted portion of valve e, and through the channel During this time, the low-pressure steam contained within the receiver will flow into the annular chamber b', acting therein on a piston-surface of a size like the dierence between the working-surfaces of the two pistons. As, now, also chamber b2 is (constantly) filled with the low-pressure steam, there is, consequently a pressure counteracting the pressure of the high-pressure-steam, the said counteracting pressure being produced by the influence of thelow-pressure steam upon the lower side of the high-pressure piston. During the-expansion-period the valves ef are in their middle position, as shown in the drawing. It, there after, the valves are lowered, the high-pressure cylinder will come into communication with the receiver proper c, while chamber b of the low-pressure cylinder communicates through the outlet lo either with the atmosphere, or with a condenser. The chambers a and b2, as well as the receiver, are, thus, filled with steam of equal pressure, and the piston on its return stroke is acted on by a pressure constituted by theinfiuence of the low-pressure steam on a piston-surface of a size like that of the dilerence between the working.- surfaces of the two pistons.

Besides the chamber b2 of the low-pressure cylinder, also the annular space c around the high-pressure cylinder forms part of the receiver. Therefore, the latter cylinder as well as the small piston is constantly cooled bythe low-pressure steam present within said space c', while the Vlow pressure steam present within chamber b2 constantly hea-ts the lowpressure cylinder-as well as the large piston. By reason of these functions of said spaces, the engine is specially adapted to be driven by superheated steam. There is, then, the further advantage, that stuffing-boxes may entirely be dispensed with.

Having thus fully described the nature of this invention, what I desire to secure by Letters Patent of the United States isl. In a steam-engine having two co-axial cylinders of different diameter, and two corresponding pistons dividing the said cylinders into three compartments, the combination with areceiver, constantly communicating with the outer compartment of the larger cylinder, and with a valve adapted to connect the smaller cylinderl alternately with theinlet and with said receiver, of another valve adapted to connect the middle compartment alternately with the receiver and with the outlet, for the purpose as described.

2. In a steam-engine having two co-axial cylinders of different diameter, and two cor-' responding pistons dividing the said cylinders into three compartments, the combination with a receiver, constantly communicating with the outer compartment of the larger cylinder, and with a Valve adapted to connect the smaller cylinder alternately with the inlet and with said receiver, of another valve adapted to connect the middle compartment alternately with the receiver and with the outlet, the port operated by said latter valve being adapted to lead the steam into the said middle compartment, as Well as ont of the same, for the purpose as described.

In testimony whereof I have signed this specification in the presence of two subscrib- 25 ing Witnesses.

WILHELM SCHMIDT. Witnesses:

R. HERPIOH, E. SCHULTZE. 

